I'm reasonably sure this comes down to the fact that the business is the property of the owner and nobody has the moral right to tell him/her what they can or cannot do with the business. The owner of the business has the right to place whatever stipulations they want on employment at their company.
edit: In no way, shape, or form does that mean I agree with or condone the owner's decision.
edit: In no way, shape, or form does that mean I agree with or condone the owner's decision.